> On Tue, 13 Feb 2007 17:55:31 -0600 Eric Van Hensbergen <[EMAIL PROTECTED]> > wrote: > +int v9fs_prepare_write(struct file *file, struct page *page, > + unsigned from, unsigned to) > +{ > + if (!PageUptodate(page)) { > + if (to - from != PAGE_CACHE_SIZE) { > + void *kaddr = kmap_atomic(page, KM_USER0); > + memset(kaddr, 0, from); > + memset(kaddr + to, 0, PAGE_CACHE_SIZE - to); > + flush_dcache_page(page); > + kunmap_atomic(kaddr, KM_USER0); > + } > + SetPageUptodate(page); > + }
This will mark the page uptodate while the piece between `to' and `from' is uninitialised. A concurrent pagefault can come in and permit a read of that uninitialised data. Because filemap_nopage() doesn't lock the page if it is uptodate. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/